The added zombies are already having an adverse effect on the game, the 3000+ zed counts are making in town looting nearly impossible, thus making those first couple hours exponentially harder. Add in the already all too common PK, and the fact that gear, ammo, and food just became even more valuable and you will find many more people killing for simple gear between towns etc. You may have just made the game an impossible cluster fuck. I would suggest taking into account all of the reprocussions of making such a drastic change BEFORE you do so.